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Why active low signals are used in digital design?

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anoop12

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Hi,
Most of the time, it is seen that active low signals are used in the digital design.
What must be the reason for this?

regards
anoop
 

IanP

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Re: active low signals

Most control signals in electronics are active-low signals (usually reset lines, chip select lines and so on). This stems from the fact that most logic families can sink more current than they can source, so fanout and noise immunity increase. (The reason for this is ultimately related to the fact that electrons are negatively charged.) It also allows for wired-OR logic if the logic gates are open-collector/open-drain with a pull-up resistor. Examples of this are the I²C bus and Controller Area Network (CAN).
https://en.wikipedia.org/wiki/Active_low

Regards,
IanP
 
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